Pension and Other Benefit Plans - Pension Plan, Assumptions and Other Selected Information (Details) - USD ($) $ in Millions	Mar. 31, 2025	Mar. 31, 2024
Benefit Plans with Projected Benefit Obligation in Excess of Plan Assets
Projected benefit obligation	$ 1,048	$ 1,113
Accumulated benefit obligation	994	1,047
Fair value of plan assets	617	646
Benefit Plans with Accumulated Benefit Obligation in Excess of Plan Assets
Projected benefit obligation	741	777
Accumulated benefit obligation	708	744
Fair value of plan assets	$ 324	$ 327

Amount of accumulated benefit obligation for defined benefit pension plan with projected benefit obligation in excess of plan assets.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-3

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Amount of plan asset for defined benefit pension plan with projected benefit obligation in excess of plan assets.

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Amount of accumulated benefit obligation for defined benefit plan with accumulated benefit obligation in excess of plan assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480482/715-20-55-17

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480506/715-20-50-3

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